Add allow_failure field to commit status API

Closes #3196

CHANGELOG

@@ -3,6 +3,7 @@ Please view this file on the master branch, on stable branches it's out of date.
 v 8.2.0 (unreleased)
   - Force update refs/merge-requests/X/head upon a push to the source branch of a merge request (Stan Hu)
   - Improved performance of finding users by one of their Email addresses
+  - Add allow_failure field to commit status API (Stan Hu)
   - Improved performance of replacing references in comments
   - Show last project commit to default branch on project home page
   - Highlight comment based on anchor in URL

doc/api/commits.md

@@ -22,7 +22,8 @@ Parameters:
     "author_name": "Dmitriy Zaporozhets",
     "author_email": "dzaporozhets@sphereconsultinginc.com",
     "created_at": "2012-09-20T11:50:22+03:00",
-    "message": "Replace sanitize with escape once"
+    "message": "Replace sanitize with escape once",
+    "allow_failure": false
   },
   {
     "id": "6104942438c14ec7bd21c6cd5bd995272b3faff6",
@@ -31,7 +32,8 @@ Parameters:
     "author_name": "randx",
     "author_email": "dmitriy.zaporozhets@gmail.com",
     "created_at": "2012-09-20T09:06:12+03:00",
-    "message": "Sanitize for network graph"
+    "message": "Sanitize for network graph",
+    "allow_failure": false
   }
 ]
 ```

lib/api/entities.rb

@@ -231,7 +231,7 @@ class CommitNote < Grape::Entity
 
     class CommitStatus < Grape::Entity
       expose :id, :sha, :ref, :status, :name, :target_url, :description,
-             :created_at, :started_at, :finished_at
+             :created_at, :started_at, :finished_at, :allow_failure
       expose :author, using: Entities::UserBasic
     end
 

spec/requests/api/commit_status_spec.rb

@@ -18,7 +18,7 @@
       before do
         @status1 = create(:commit_status, commit: ci_commit, status: 'running')
         @status2 = create(:commit_status, commit: ci_commit, name: 'coverage', status: 'pending')
-        @status3 = create(:commit_status, commit: ci_commit, name: 'coverage', ref: 'develop', status: 'running')
+        @status3 = create(:commit_status, commit: ci_commit, name: 'coverage', ref: 'develop', status: 'running', allow_failure: true)
         @status4 = create(:commit_status, commit: ci_commit, name: 'coverage', status: 'success')
         @status5 = create(:commit_status, commit: ci_commit, ref: 'develop', status: 'success')
         @status6 = create(:commit_status, commit: ci_commit, status: 'success')
@@ -30,6 +30,8 @@
 
         expect(json_response).to be_an Array
         expect(statuses_id).to contain_exactly(@status3.id, @status4.id, @status5.id, @status6.id)
+        json_response.sort_by!{ |status| status['id'] }
+        expect(json_response.map{ |status| status['allow_failure'] }).to eq([true, false, false, false])
       end
 
       it "should return all commit statuses" do